Signaling system for railroads



Sept. 22, 1931.

s. N. WIGHT SIGNALING SYSTEM FOR RAILROADS Filed July 11, 1930 SEDGWICK N. wmm; or ROCHESTER, NEW YORK, ASSIGNOB. To GENERAL RAILWAY l atented Sept. 2 2 1931 {UNITED PATENT OFFICE SIGNAL COMPANY, or ROCHESTER, NEW ogi:

f {SIGNALING SYSTEM Fen murnonns Application filed July 11,

This invention relates totautomati'c block signaling systems for single track railroads of the type commonly known as an absolutepermissive-block system, and more fparticularly to an improvement in the signaling circuits at a passing siding to provide what is commonly known as a double distant or caution indication for opposing trains ap-; proaching a passing siding. H I

One form of an absolute-permissive-block signaling system, of the type to which the present invention relates, is shown,and;de.- scribed in detail in my prior Patent No; 1,294,736, dated February 18, 1919; and as disclosed in this patent, a special control is provided for the signal, conveniently termed the approach signal, located at a distance from the end of a passing siding and governing train movement toward the siding, so that this approach signal indicates caution when an opposing train is approaching the other end of a siding. -As disclosed in my prior patent, this desired special control ofthe approach signal is ob tained by an extraline wire extendingthe length of the passing siding. 1 n

In accordance with the present invention, it is proposed to obtain. the, desiredcontrol of the approach'signal for a passing siding, without employing an'additional line wire at the siding, by imposing anadditional'di's1 tinctive control uponthe usual signal or line circuit extending the length ofthe; siding, thereby eliminating the additional-line wire ordinarily required for the double distant control of the approach signal. 1, a

More specifically, in accordance with the present invention, provisionsare made for energizing the homerelay line circuit at a passing siding with currents of different intensitiesas well as differentpolarities so as to transmit over this line circuit an additionalcontrol which' maybe employed for obtaining the double distant indication of the approach signal. 1

The characteristic features, objects, and advantages of the invention will be in part apparent, and in'part pointed out, as ,the description'progressesf The accompanying drawing illustrates in 1930. Serial in. 467,223.

a simplified anddiagrammatic manner one specific embodiment of the invention applied to a typical A. P. B. system of the type disclosed in myprior patent, above mentioned. This drawingillustrates only part of the complete A. P.-B. system, many of the relaysand circuitsv having been omitted to sim= plify; the illustration. It will be readily apparent to those skilled xin the art how the principles and features of the invention, illustrated in this drawing, may be extended and -incorporated with other relaysand circuits not shown, so as to provide a complete signaling systemjor single track railroads. The stretch of track adjacent the passing siding PS is divided by insulated joints into track circuit sections inthe usual'way, each havingatrack. battery and a track relay. The track relays are shown conventionally by dotted lines and are designated 1T, 2T, etc. The approach signal 1, the entering signal 3, and the, absolute starting signal 5 governfeast-bound traflic through and past the siding; and the corresponding approach signal 6, entering signal 1, and absolute starting signal 2 govern traflic in the oppositedirection. Each ofthese signals is controlled by a. neutral-polar line relay in the. usual way, as illustrated for the approach signal 1. p In the accompanying drawing, the invention has been shown applied to the control of the approach. signal l-governing eastbound traflic (left to right) toward the passing siding PS. j I

Associated with the entering signal 3 is a slow-releasing pole-changer relay 31 C and a special relay 3X. Associated with the signal 5 is a similar pole-changer relay 5P0, and a directional stick relay 5S. f

The relays and circuits are shown in the drawing in the normal condition existing when no trains are present in the portion of track under consideration, all the signals indicatijng'clear or proceed. The line relay 5HD, controlling the signal 5, is normally energized by a circuit in the same way as in my prior patent above mentioned, this circuit being only partially shown and including the front contacts of 11, relay 5PC to indicating-theother terminal of said battery.

The line relay 3I-ID, controlling the nal 3, and the additional special relay 3 are connected in multiple, and are normally energized over a line circuit which may be traced from G (indicating a connection to the usual common return wire of the system), through the front contact 12 of the track relay 3T, line wire 13, front contact 14 of the track rela 4T, wire 15, front contact 16 of relay 5P wires 17. and 18, front contact 19 of relay 5PC, wire 20, lower terminal of the battery 21, wire 22, front contact 23 of relay 5P0 to C.

This circuit energizes the relay 3H1) with the normal polarity and causes the signal 3 to indicate clear or proceed.

With the relays 3H1) and 3X both energized, the pole-changer relay 3P0 at the Sig-- nal 3 is energized by a circuit which may be traced from front contact 24 of relay 3X, wire 25, front contact 26 of relay 3HD, wire 27, relay 3PC to With the pole-changer relay 3P0 energized, the line relay lHD, controlling signal- 1, is energized with the normal polarity over a line circuit readily traced on the drawing, and consequentlythe signal 1 indicates clear or proceed.

Assume that a west-bound train, travelling from right to left enters the stretch of single track at the right of the passing siding PS. When this train enters this stretch of single track, it causes all of the opposing signals, including the startingsignal 5, to indicate stop, through the action of the tumble-down circuits, as explained in detail in my prior patent above mentioned. When a relay 5HD is thus tie-energized, to cause the signal 5 to indicate stop, the energizing circuit for the relay 5P0 is broken at the front contact 10 of the relay 5HD.

Under these conditions, with the relay 5P0 down, the relays 3HD and 3X are energized in multiple over a different circuit, starting at C, through the front contact 12 of the track relay 3T, line wire 13, front contact 14 of track relay 4T, Wire 15,- back com tact 16, wire 22, upper terminal of the battery 21, wire 28, resistance 29, wire 30, back contact 31 of relay 58, wire 32, back contact 19 of relay 5P0, wire 18, and through the back contact 23 of relay 5P0, to C.

The resistance 29 included in this circuit reduces the current intensity to a valve suflicient to energize the relay 3HD effectively to close its contacts, but insufficient to energize the relay 3X eifectively. The relay 5PC, tie-energized, reverses the polarity of the current applied to the relay 3HD, thereby causing the signal 3 to indicate caution. The opening of the front contact 24 of the relay 3Xbreaks the energizing circuit for the relay 3P0; and the de-energization of the relay 31 C reverses the polarity of the current for energizing the circuit lHD, so that the-signal 1 also" indicates caution.

Thus, when a west-bound train approaches the siding PS, the starting signal 5 indicetes stop, and the approach signal 1 and entering signal 3 also both indicate caution, providing the double distant or caution indication, characteristic of an A. P. B. system, and aflording the necessary protection to train movement, as ex l'ained in my prior patent above mentionedi When an east-bound train passes the signal 3, o ning the front contact 12 of the track re ay 3T and de-energizing the relay 3RD, inso doing, the pole-changer relay 3P0 is (lo-energized, reversing the polarity of the line circuit for the relay lHD so that the signal 1 indicates caution.

When this east-bound train passes the signal 5, it picks up the directional stick relay 58 in the usual way. The pick-up circuit for the relay 5S may be traced from through the circuit controller 33 operated by the signal 5, wire 34, back contact 35 of track relay 5T, wires 36 and 37, relay 58 to The stick circuit for the relay 58 may be tracedfrom through the back contact 380i the line relay 5HD, Wire 39, front contact 40 of relay 58, wires 41 and 37, relay 58' to This stick relay 5S is picked up by an east-bound train passing the signal 5, since the back contact 35 of the track relay 51 is closed beiore the circuit controller 33 of the signal 5 opens, but is not energized for a west-bound train movement, since the circuit controller 33 opens before the track relay back contact 35 is closed, all in a manner' iamiliar to those skilled in the art and explained more in detail in my prior patout above: mentioned.

-With the directional stick relay 5S energized by such an east-bound train passing the signal 5, the relay 5P0 is de-energized the some as for a west-bound train movement, to reverse the polarity of the energazing current-for the relays 3HD and 3X;

t the resistance 29 is not included in this circuit, being shunted by wire 42, front contact 43 of rela 5S-and wire 44, so that the full voltage 0 the battery 29 is applied to this circuit, and relay 3X, as well as the relay 3HD, is efl'ectively energized. Consequently, the pole-changer relay 3P0 remains energized, and the signal 1 may indicate clear or proceed for a following train the same as in double-track signaling.

The same scheme of control is employed for the approach signal 6.

From the foregoing it can be readily understood how the desired double distant or caution control for an A. P. B. system is attained, without an additional line wire extending the length of the siding. The line circuit for the relay 3HD, in addition to the control of its polarity to govern the caution and proceed indications of the entering signal 3, is also energized with different current values or intensities due to the inclusion and exclusion of the resistance 29, in accordance with the directions of trains approaching and passing the starting signal 5, thereby providing through the medium of the special relay 3X, an extra control for the relay 3PC, which may be utilized to obtain the desired double distant control of the approach signal 1. It will be evident that controlling the current value or intensity of the energizing circuit for the relay 3HD by inserting and cutting out a resistance is only one way of superimposing an additional controlling condition upon this circuit; and it is contemplated that any other suitable means may be adopted for the same purpose.

The particular construction and arrangement of circuits shown and described, represents only one particular embodiment of the invention, and is merely typical or illustrative of the principles, functions, and mode of operation of the invention; and it should be understood that various adaptations, modifications, and additions may be made in this particular arrangement without departing from the scope of the invention.

What I claim is 1. In an automatic block signaling system of the type described, two signals governing traffic toward the end of a passing siding, a line circuit, relaysenergized by said line circuit and responsive to variations in the current intensity for controlling said signals, and means responsive to the direction of movement of trains for controlling the current intensity in said energizing circuit.

2. In a signaling system of the type described, an approach signal, a pole-changer relay governing the indications of said signal, two relays controlling said pole-changer relay and responsive to diiierent current intensities, a line circuit for energizing said two relays, and means for governing both the polarity and current intensity of energization of said line circuit.

3. In a block signaling system of the type described, an entering signal at the entrance to a siding governing traflic toward the siding, an approach signal in the rear of said entering signal governing traific in the same direction, a neutral-polar line relay controlling the indications of said entering signal, a line circuit for said relay, means responsive to the direction of movement of trains for ener izing said line circuit with currents of difl erent polarity and different intensities, and means controlled over said line circuit and responsive to the intensity of the energization thereof irrespective of its polarity for controlling the indications of said approach signal.

4. In a signaling system of the type described, an approach signal at a distance from the end of a passing siding and governing trafiic toward the siding, a line circuit governing the indications of said signal, a pole-changing device for controlling the polarity of energization of said line circuit, and means for governing said device comprising a line circuit extending along the siding and two relays both energized over said line circuit, one of said relays being responsive to the polarity ofenergization of said line circuit irrespective of its intensity, and the other relay being responsive to the intensity of energization of said line circuit irrespectiveof its polarity.

5. In a signaling system of the type described, an approach signal at a distance from the end of a passing siding and governing trafiic toward the siding, a polechanging device controlling the indications of said signal, a line circuit extending along the siding, a neutral-polar relay energized over said line circuit for controlling said pole-changing device, and means responsive to the intensity of energization of said line circuit irrespective of its polarity for also controlling said pole-changing device.

6. In a block signaling system of the type described, an entering signal at the entrance to a siding governing trafiic toward the siding, an approach signal in the rear of said entering signal governing traflic in the same direction, a neutral-polar line relay controlling the indications of said entering signal, a line circuit for said relay, means for energizing said line circuit with current of one or the other polarity depending on track occupancy, a stick relay energized or deenergized in accordance with the direction of movement of a passing train for applying current of a third character to said line cir- 

